Project Summary TRD 1 The proposed research in TRD Project 1 is to develop novel optical coherence tomography (OCT)-based techniques and tools for measuring the mechanical properties and parameters as well as acoustic transduction in tissues. The focus on tissue biomechanics responds to the emerging opportunity to harness OCT's unique capabilities to obtain quantitative maps of tissue vibration, deformation, strain, and force at high precision and high spatiotemporal resolution. Specific aims are directly motivated by the challenges identified in Collaborative Projects. Aim 1 is to develop probe-based OCT vibrography for analysis of middle and inner ears. A cellular- resolution probe with a diameter of 1 mm will be developed, tested, and validated in vivo with genetically modified mouse models of hearing disorders. Furthermore, the ability to image the 3D structure and sound- driven vibration of the inner working of human cochlea in cadaveric specimens will be established. Aim 2 of the proposed research is to develop corneal elastography based on noncontact acoustic vibration. Finite-element methods to map corneal stiffness from vibrational images will be developed and tested in a pilot human study involving normal and LASIK-treated subjects. Aim 3 of TRD-1 is to develop micro-sized inclusion sensors for OCT elastography for mapping force, strain, and stiffness with greatly enhanced accuracy. This tool and computational algorithm will be tested for quantitative biomechanics mapping of the optic nerve head. Through these combined aims, TRD-1 strives to help the community advance fundamental knowledge and improve the diagnosis and treatments of diseases through technical innovations.